Haven't tried it on my team, but man is it insanely strong on the enemy team.
Halves incoming damage, and then heals half of THAT.

Do 1000 normally, they take 500 and heal 250. They. Never. Die. And that's assuming they're not rocking another mitigation like MR Buff, or DEF Buff, or *gulp* Reflect.

I hope the player version is that strong. Though I don't think there is a character that gives it to everyone, is there?